GaN-HEMT on 100mm Diameter Sapphire Substrate Grown by MOVPE
Yohei Otoki, *Michio Kihara, *Takeshi Tanaka, *Kazuto Takano, **Toshihide Kikkawa and
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**Fujitsu Laboratories Ltd, ***Fujitsu Quantum Devices Ltd.
Keywords: GaN-HEMTs, 100mm diameter, sapphire substrate, MOVPE, uniformity, DC characteristics
Possibility of using GaN-HEMT grown by MOVPE on 100mm sapphire substrates in the industry has been investigated. Bowing of 2 µm thick GaN on 100mm substrate was 40 to 60 µm. Excellent uniformity of sheet carrier concentration of HEMT structure wafer across the wafer was obtained by optimizing the gas flow system and thermal circumstance to avoid pre-reaction between Ammonia and III group gases. FETs with 0.8 µm gate were well fabricated in spite of the bowing and good pinch-off characteristics and high breakdown voltage over 100V was obtained. Standard deviation of Vth was 50mV across the wafer (average Vth=-2.6V), that of Idss and Gm-max were 11mA (average Idss=300mA/mm) and 5.3mS (average Gm-max=145mS /mm), respectively. This uniformity is good enough for mass production. These results are very encouraging as they show the high possibility to successfully achieve mass production of 100mm wafers.